2003 GMC Sierra 1500 Pickup Owner's Manual - Page 236

DlSP (Display): Press this knob to see how long the current track has been playing. ET and the elapsed time will appear on the display. To change the default on the display (track or elapsed time), push the knob until you see the display you want, then hold the knob for two seconds. The radio will produce one beep and selected display will now be the default. BAND: Press this button to listen to the radio when a CD is playing. The discwill stop but remain in the player. CD AUX (Auxiliary): Press this button to play a CD when listening to the radio. Compact Disc Messages If the disc comes out, it could be for one of the following reasons: You're driving on a very rough road. When the road becomes smoother, the disc should play. It's very hot. When the temperature returns to normal, the disc should play. The disc is dirty, scratched, wet or upside down. The air is very humid. If so, wait about an hour and try again. (Eject): Press this button to stop a CD when it is playing or to eject a CD when it is not playing. Eject may be activated with either the ignition or radio off. CDs may be loaded with the radio and ignition off if this button is pressed first. If the CD is not playing correctly, for any other reason, try a known good CD. If any error occurs repeatedly or if an error can't be corrected, contact your dealer. 3-81